What are the differences in birth control pills? I switched from Ortho-Tri cyclen to Alesse after asking my doctor for a lighter dose of estrogen, but have been told by friends that Nordette has the least amount and is the most effective. With all the news of hormones negatively affecting women's health, I'm very concerned.

Dear Reader,

No wonder you're confused. Currently, several dozen birth control pills are on the market, and the mixed messages coming in from advertisements, your friends, and your health care provider can make it even harder to distinguish what's best for you. Generally, two different types of pills are being prescribed today:

Combination pill

This is the most commonly prescribed type of pill, and contains small doses of both estrogen and progestin. Within this, there are even more groupings depending on whether each includes more estrogen than progestin or vice versa. Commonly prescribed combo pills include Ortho Tri-Cyclen, Yasmin, and the two you mentioned above (Alesse and Nordette).

Progestin-only pill

Also called the "minipill," the progestin-only pill is usually prescribed when women using the combo pill want to decrease some of the side effects associated with estrogen or when life changes (beginning to nurse a child, for example) hinder using synthetic estrogen. Early on, progestin-only pills can cause more irregular menstruation than the combination pill, usually decreasing the number of periods for about the first year. Progestin-only pills have seen less airtime also because other progestin-only methods exist that have become more popular, including Depo-Provera and intrauterine devices (IUDs).

While Nordette (similar to Alesse) does contain less estrogen than Ortho Tri-Cyclen, Alesse contains only 20 micrograms of estrogen while Nordette contains 30 micrograms. As a matter of fact, most birth control pills nowadays contain less estrogen than earlier types of oral contraceptives. Comparing estrogen is straightforward since all pills use the same type of estrogen; this makes it possible to compare dosages simply by quantity. On the other hand, because pills use different types of progestin (each of which has a different strength), it's much harder to compare progestin levels across pills.

Synthetic hormones are a much debated topic lately, especially with all the concern surrounding estrogen and breast cancer. Studies are not yet conclusive regarding whether there is any link between the two. Also, the studies that are currently in progress have been conducted only with the higher dose pills (more than 50 micrograms of estrogen). None are in the works for the more common, low dosage variety, so we might not have an answer to this question for quite some time.

Outside of the larger long-term concerns, every pill has positive and negative side effects — changes in acne, weight, or mood, to name a few. Many of these effects can be considered on a physiological level. For instance, an increase in acne might be countered by a higher dose of estrogen and less progestin, while persistent headaches might be mollified by lower doses of both. Because of the many factors that come into play when choosing a pill, it's important to constantly self-evaluate so that you can give your health care provider an accurate picture of how your body is handling the hormones. Telling your doctor you'd like less estrogen is a great start. However, a more clear, useful approach is either to describe your symptoms or to explain what you are worried about or how you got to this conclusion of wanting to use less estrogen. The more your health care provider knows, the better the decision both of you can make regarding your choice of contraception (be it the pill or any other flavor).